Lubricating oil



Patented June 3, 1947 LUBRICATING OIL Bert H. Lincoln, Ponca City,Okla., and Gordon D. Byrkit, Niagara Falls, N. Y. 1

N Drawing.

15 Claims. 1

Our invention relates to lubricating oils and more particularly toimproved lubricating oils of high film strength which are non-corrosivetoward easily corroded bearing materials.

This is a division of our copending application Serial No. 405,213,filed August 2, 1941, now Patent No. 2,395,889, issued March 5, 1946,which, in turn is a continuation-in-part of our application Serial No.275,488, filed May 24, 1939 (now Patent No. 2,257,750, issued October 7,1941.)

In the development of new automotive and other types of engines,increased power and other requirements have led to the introduction ofbearing metals, alloys, and mixtures which are readily attacked byoxidation products of the lubricant. Some of these newer bearincompositions are cadmium-silver, copper-lead and a1- loys of lead withalkali, and alkaline earth metals. These comparatively soft metals arecorroded readily by oils which have been used for a short time in theengine. One method of overcoming this difficulty would be to use moreresistant bearing compositions, and anotherwould be to use an oil whichdoes not develop these corrosive materials during use. Still anothermethod would be to use a lubricant containing a material which wouldreact with and render. inert the corrosive products as rapidly as theyare formed. Our invention is not concerned with the first method butwith the other two possibilities. Various addends have been proposed tobe added to lubricants for the purpose of inhibiting the formation ofcorrosive materials during use. These may be called antioxidants, sincethey increase the time of use before rapid oxidation begins to occur andalso decrease the rate of oxidation after it has started. Variousaddends have also been proposed to be added to lubricants for thepurpose of reacting with such corrosive materials, as may in timebeformed, and removing them from the oil so that they are unable tocorrode the parts being lubricated. These may be called precipitants.The present invention proposes addends combining these two capabilitiesin the same molecule to give an un expectedly superior activity in bothrespects over what would be predicted from a simply additive efiect.

Certain compounds are adsorbed or absorbed by metals forming tenaciousfilms at the surface of metals which are able to stand high pressures.X-ray diffraction methods have shown that compounds containing highlypolar molecules, that is, molecules of unsymmetrical charactercontaining an atom or group of atoms ex- Original 1941, Serial No.405,213. plication May 16, 1945, Serial application August 2,

Divided and this aphibiting a secondary or residual valence, tend to.

a film of the compound in which there is a regimentation of moleculesoriented with respect to the surface of the metal by which they areadsorbed or absorbed.

One object of our invention is to provide a substantially non-corrosivelubricant for use with the newer, easily corroded bearing compositions.It is to be noted, however, that the improved lubricant here describedis advantageously employed with all typesof bearings, since it is lesscorrosive during use with any of the metals commonly encountered inpractice.

Another object of the invention is to provide a lubricant inhibitedagainst oxidation during use.

A further object of our invention is to provide a lubricant containingan addend capable of reacting with or otherwise rendering inert suchcorrosive products as may be formed during extended use.

4 Other objects of the invention will appear in the followingdescription.

Our invention consists of the addition to lubricants of all kinds ofsalts or soaps of certain sulfur-bearing acids. 'These salts may be ofdiverse types, and both the'anionic and cationic parts of these soapsmay be varied. Thus the cations may be purely organic or purely metallicor organometallic. In introducing sulfur into the acid. radical of oursalts, we have found that certain compounds rich in sulfur react withunsaturated acids to yield peculiarly effective addends for lubricatingoils. By compounds rich in sulfur, we mean those containing more than 50per cent of sulfur in their molecular composition. Examples of thesereagents are phosphorus pentasulfide, phosphorus pentasulfide,phosphorus trisulfide, and alkali metal polysulfides (sodium disulfide,potassium trisulfide, and higher sulfides). These particular sulfurizingagents yield particularly effectively bound sulfur in the molecule ofthe sulfurized acid. The herein described salts of such su1- furizedacids are extraordinary detergents and inhibitors of oxidation whenaddedto lubricants of all kinds. They contain no corrosive halogen andare more effective inhibitors than salts of acids containing sulfur inknownstructures such as sulfonic acids, sulfones, thioethers,heterocyclic sulfur, and the like. g

In the following examples, any of the cations may be usedwith any of theanions to form these I. Anions A. Alkali metal polysulfide-treatedacids 1. Sodium pen-tasulfide treated "oleic acid 2. Sodium tetrasulfidetreated linoleic acid 3. Sodium trisulfide-treatedlinolenic acid 4.Sodium 'disulfide-treatedbelaidic acid 5. Potassium pentasulfide-treatedcorncilaci'dS 6. Potassium trisulfide treated soy oil acids 7. Potassiumtetrasulfide treated lard oil acids 8. Lithium pentasulfide-treatedtungoil acids 9. Lithium tetrasulfide treated abi'etic acid Lithiumtrisulfide treated choliczacid A mm'ioni u m pentasulfida treatednaphthenic acids -3. Phosphorus sulfide treated acids (containingphosphorus and :sulfur) 1.. Phosphorus penta sulfidetreated corn; oilacids 2. Phosphorus" trisulfide-treated;

corn oil. acids .3. Phosphorus :penta an 1 it i d e- :treated, soyOilzdGidS v4. Phosphorus: pentas u-l'f 1 detreated 'lolei'cjacid 5.Phosphorus penta s u 1 f i de treated linoleic: acid IL Cations -A-.Metallic:

l. Grouprl Lithium, sodium,;pqtassium, rubidium, cesium, copper 2.rC-lrolupz Calcium,-strontium,,bari-- .um, beryllium, =magnesium, zinc,cadmium,

These organo-metallicsoaps may have, in the organo-metallic cation an.organic radical or radical's of "the aliphatic orcarbocyclic'orheterocyclic series. The metallic element of the compoundmaybe anyone of a number of which, the following are'representative. Forconvenience, we shall indi- 4 list them in accordance with theiroccurrence in the periodic table:

Group II Magnesium Zinc Cadmium Mercury Group III Boron AluminumfI'hallium Group IV Silicon Tin Lead Group V Arsenic Bismuth AntimonyGroup VI Tellurium Selenium Some of the organo-metallicradicals whichmay act as cations informingthe soaps to be used are:

GroupwlI V Phenylmagnesiurn Propyl magnesium Methylzinc CresylzincXylylcadmium Iso-Amylcadmium Butylmercury MesitylmercuryNitrophenylmercury Naphthylmercury Group III Phenylboron (II)Diphenylboron (I) o-Xylylboron (II) Dipropylaluminum DiethylthalliumDiphenylthallium Di-p-tolylthallium Group IV TriphenylsiliconTriphenylgermanium Di-isoamyltin Di-alpha-naphthyltini DiphenyltinEthylphenyltin iso-Propyltin Triethyltin Triphenyltin Di-isobutylleadDiethyllead Diphenyllead Triphenyllead- Group V EthylarsenicDiphenylantimony Di-alphanaphthylbismuth Diphenylbismuth Group VIPhenyltellurium Diphenyltellurium Triphenyltellurium Phenylseleniumtached to the metalror inthe anion of the soap. an additional element,or combination-0t elements includingthe halogens sulfur, phosphorus,

76 nitrogen, or oxy en Some of the combinations of the cations with theanions are listed below, but it is obvious that all the possiblecombinations serve as examples of the invention when admixed withlubricating oils or greases:

.Sodium salts of sulfurized corn oil acids Aluminum salts of sulfurizedbeta fat Stannous salts of sulfurized corn oil acids Stannic salts ofsulfurized corn oil acids Ammonium salts of sulfurized oy oil acidsTriphenyltin salts of sulfurized corn oil acids Diethylthallium salts ofsulfurized corn oil acids Phenylmagnesium salt of sulfurized oleicacidNitrophenylmercuric salt of sulfurized lard oil acids 10.Diphenylthallium salt of sulfurizedsoybean oil acids Triamylammoniumsalts of acids Calcium salts of sulfurized corn oil acids Lead salts ofsulfurized beta fat Barium salt of sulfurized oleic acid, sulfurizedwith sodium pentasulfide Triphenyltin salt of sulfurized oleic acidBenzyltrimethylammonium salt of sulfurized oleic acid,'sulfurized withphosphorus pentasulfide Calcium salt of sulfurized oleic acid,sulfurized with sodium pentasulfide Calcium salt of sulfurized oleicacid, sulfurized with sodium trisulfide Benzyltrimethylammonium salts ofsulfurized corn oil acids, sulfurized with sodium pen- 'tasulfide 20.Triphenyltin salts of sulfurized soybean oil acids, sulfurized withphosphorus penta- While all of the above usual results described, wehave found that particular emphasis should be placed on theorganometallic salts of sulfur-bearing acids because they are especiallyeffective antioxidants and corrosion inhibitors; furthermore the tinsalts (metallic or organo-metallic) deserve notice as exhibiting theseproperties to a high degree.

The addends of this invention have a dual action in a lubricant. Oneaction involves increased load-carrying ability and/or oiliness, whileanother action is directed to the stability of the lubricant. Forload-carrying capacity, quantities ranging from 0.1 per cent to about10.0 per cent must be added. As an anticorrosive agent and/or anantisludging agent, much smaller amounts must be used, ranging fromapproximately 0.001 to 0.1 per cent. The action of the organo-metalliccompounds is specific but difiicult to understand. These compounds maybe added to any type of hydrocarbon lubricants but show an unusual valuein highly refined and solvent-treated lubricants.

The lubricating oil portion of the blends of our invention may beso-called mineral or hydrocarbon oils or may consist of wholly orcontain only in part certain fatty oils including corn oil, soybean oil,lard oil, and the like. The blends may contain voltolized oils orsynthetic oils of lubricating viscosity. Soap-thickened or otherwisethickened oils used as greases may be employed. Addends for otherpurposes such as pour point depressors may be present.

These compounds have varying degrees of solubility in hydrocarbon oil.In some cases, it is necessary to use a solvent for the compound or 11.sulfurized lard oil examples give the unto form colloidal suspensions ofthe compound in oil.

The film strength and oxidation characteristics of solid and semisolidgreases may be improved by the addition of small amounts of our metallicsoaps thereto. The chemical purity for use as extreme pressure additionagents is not critical. All that is important is that no corrosivecontaminants be present. Mixtures of a number of these compounds may beemployed.

It will be understood that'certain features and subcombinations are ofutility and may be employed without reference to other features andsubcombinations. This is contemplated by and is within the scope of ourclaims. It is further cbvi ous that various changes may be made indetails within the scope of our claims without departing from the spiritof our invention. It is therefore to be understood that our invention isnot to be limited to the specific details shown and described.

We claim:

.1. A lubricant comprising in combination a major proportion of oil oflubricating viscosity and a minor proportion, sufficient to stabilizesaid oil against oxidation, of a salt of a sulfurized relatively highmolecular weight carboxylic acid, said carboxylic acid being unsaturatedand being sulfurized by reaction with sodium pentasulfide.

2. A lubricant comprising in combination a major proportion of oil oflubricating viscosity and a minor proportion, suflicient to stabilizesaid oil against oxidation, of a metallic salt of a sulfurizedrelatively high molecular weight carboxylic acid, said carboxylic acidbeing unsaturated and being sulfurized by reaction with sodiumpentasulfide.

3. A lubricant comprising in combination a major proportion of oil oflubricating viscosity and a minor proportion, sufiicient to stabilizesaid oil against oxidation, of an organo-metallic salt of a sulfurizedrelatively high molecular weight carboxylic acid, said carboxylic acidbeing unsaturated and being sulfurized by reaction with sodiumpentasulfide.

4. A lubricant comprising in combination a major proportion of oil oflubricating viscosity and a minor proportion, sufficient to stabilizesaid oil against oxidation, of a salt of an organic base and asulfurized relatively high molecular weight caboxylic acid, saidcarboxylic acid being unsaturated and being sulfurized by reaction withsodium pentasulfide.

5. A lubricant comprising in combination a. major proportion of oil oflubricating viscosity and a minor proportion, sufiicient to stabilizesaid oil against oxidation, of a salt of a sulfurized relatively highmolecular weight aliphatic carboxylic acid, said aliphatic carboxy 'cacid being imsaturated and being sulfurized by reaction with sodiumpentasulfide.

6. A lubricant comprising in combination a major proportion of oil oflubricating viscosity and a minor proportion, sufiicient to stabilizesaid oil against oxidation, of a metallic salt of a sulfurizedrelatively high molecular weight aliphatic carboxylic acid, saidaliphatic carboxylic acid being unsaturated and being sulfurized by reaction with sodium pentasulfide.

'7. A lubricant comprising in combination a major proportion of oil oflubricating viscosity and a minor proportion, sufficient to stabilizesaid oil against oxidation, of an organo-metallic salt of a sulfurizedrelatively high molecular weight aliphatic carboxylic acid, saidaliphatic carboxamalgam i7ylicaacid'beingzunsaturatedzandibeing:suliurized by reaction with sodiumpentasulfide.

:lubricant -.comprising in -combination a mafior-iproportion 'JQf oil401' alubrioating :wiscosity and anminor;picportionysufificientatostabilize said oi1 against oxidation; of a saltof anuorganic base and a sulfurizedarel'ativelyhighmolecular weightaliphatiwcarboxylic fiCid,'-::Sai'd aliphatic .carboxy-lic facid beingunsaturated and being asulfurized by reaction-with sodium ,pentasuifide.

r9. ii-lubricant comprising in combination a major aproportion of :oilof .-lubr-icatingwviscosity and aminoriproportion, sufiicientto-stabilize said oilea-gainst oxidation, of-a:salt of -su1iurized-soybean: oil acids; said soybean oil acids :being sulfiuri-zed by:reaction @with sodium .wpentasulfide.

1 -10. .A lubricant comprisin in combination a major proportion of oil.offlluloricatin'g viscosity and a: minorproportion,l-sufficient-torstabilize said oilaagainst-oxidation, of 2 asalt. of sulfurized corn oil acids, said corn oil acids being sulfurizedhy reaction withsodium pentasulfide.

11. 1A [lubricantcomprising in combination a major proportion-of oil :oflubricating viscosity and atminonproportion,r-suflicient m-stabilize.said oilUagainstoxidation, ofna salt of sulfur-ized oleic acid, said.oleic acid being ,sulfurizedrby :reaction withsodiumpentasulfide. I'VI-ZRAQJubricant comprising incombination a major pmportioniof .oil .oflubricatin miscos-ity and atminorvproportion, suifioienti to,stabilizevsaid 0311 against oxidation, 45f .ebenzyltrimethyl ammonium,salts .of sulfurized corn oilhacids said corn oiliacids beingsfilfurized by reaction .Withisodiumpentasulfi'de.

.213. A lubricant comprising inucombination a 8 major proportion:iofroilof lubricating viscosity F-a minor proportion, sufiicientto'stabilizesaid oil 1 against ioxidation, aof the'calcium :salt ofasulfurize'd oleic acid, said oleicsacid being sulfur-med by reactionwith sodium pentasulfide.

14. A lubricant comprising .in .combinationra major proportion of oil..of lubricating viscosity and aminor proportion,sufficientitoostabilizasa-id oil against oxidation, .ofvtriphenyltinstrumminfurized soybean oil acids, said w. soybean oiL acids beingsuifurized .by. r. reaction with sodium ;pentasulfide.

15. A lubricant comprising in combination a major proportion .of ,oil oflubricating .x'tiscosity and from 0.001 to 10 vper centof ra salt-ofaassulfurized relatively high molecular weighticarboxylic iacid saidcarboxyliciacid being unsaturated and being sulfurized 'by reaction:withnsodium pentasulfide.

BERT H. LINCOLN.

=GORDON 1D. BYRKIT.

l REFERENCESCITED The following references are pf'zrecordiin the fileaof :this patent:

UNITED STATES PATENTS Number Name Bate 1,590,800 "Becker June 29,-19262,212,189 Brunstrum 'Augf20, 1940 2,237,096 'Dearborn Apr. 1, '19412,242,174 Burk May'13, 1941 2,246,282 'Zimmer 'June17','1941 2,341,453'Lieber .Feb.-8, 1944 2,361,957 Musselman .'"1' T0v;""7, 1944

